1. Field of the Invention
The present invention pertains to a phototherapy system and method for providing a therapeutic light treatment to a patient, and, in particular, to a phototherapy system and method in which a bulb switching mechanism automatically replaces a failed bulb with a new bulb, and to a phototherapy system having an improved fiber optic cable coupling system.
2. Description of the Related Art
Phototherapy devices that generate radiant energy, typically a visible light having a particular wavelength, and that transmit the energy to a surface of a patient are known. In one type of phototherapy device, light from a halogen bulb is transmitted to the surface of the patient to treat jaundice. An example of such a conventional phototherapy device is the Wallaby(copyright) II phototherapy system distributed by Respironics Inc. of Pittsburgh, Pa.
Such conventional phototherapy devices typically include a source of illumination and a fiber optic cable having a proximal end coupled to the source of illumination for transmitting the light to the patient. A fiber optic panel is located at the distal end of the fiber optic cable to provide a blanket of light that can be positioned next to the patient""s skin. A concern with such conventional devices is maximizing the lifetime of the device before the bulb or bulbs that produce the light have to be replaced.
This problem is addressed in conventional systems by providing two bulbs in the illumination device. If the first bulb fails, e.g., bums out, a manually actuated button is provided on the exterior housing of the illumination device. Depressing the button causes the second lamp, which is provided on a rotating carousel with the first lamp, to move into an operating position in place of the first lamp for illuminating the proximal end of the fiber optic cable. Thus, the user need not replace the bulbs until both bulbs have failed, thereby increasing the amount of time the phototherapy system can be used between bulb replacements.
This conventional approach, however, has several disadvantages. If the first bulb fails in the middle of the night, for example, while the patient is asleep, the patient or caregiver may not be aware of the failure until the following morning, thereby depriving the patient of the phototherapy during the night subsequent to the bulb failure. This problem is addressed in conventional device by providing an audible warning that is actuated upon bulb failure. Such warning devices, however, are a great cause for consternation, especially in situations where the user is unfamiliar with the purpose of the warning and/or is already apprehensive about the health of the person being treated by the phototherapy.
In addition, the conventional approach for dealing with bulb failures requires that the user manually cause the second bulb to move into position to replace the first bulb by actuating the bulb replacement button. Some patients may be unfamiliar with this procedure or have difficulty remembering to do so when the bulb replacement warning sounds. Also, some patients may have difficulty in being trained to take this necessary action once a bulb failure occurs. In addition, some patients may be physically unable to actuate the bulb replacement button, which requires depressing the bulb replacement button with a moderate amount of force sufficient to rotate the lamp carousel.
Furthermore, once the bulb replacement button has been actuated, the user cannot return the rotating carousel to the original position. Instead, the device must be delivered to a repair center where a trained technician replaces the bulbs and returns the carousel to the original position. As a result, if the user accidentally or prematurely causes the carousel to rotate, for example, by inadvertently depressing the bulb replacement button, the useful life of that device is effectively reduced. Yet another disadvantage with conventional phototherapy devices is that the mechanical rotation of the lamp carousel typically moves the lamps very rapidly and has an abrupt stop once the carousel has been rotated. This rapid movement and abrupt stop can cause mechanical shock to the filaments in the bulbs, thereby reducing lamp life.
Conventional phototherapy devices also include a system for coupling the proximal end of the fiber optic cable to the illumination device. The proximal end of the fiber optic cable receives light from the light source in the illumination device and transmits the therapeutic light to the distal end of the fiber optic cable for transmission to the patient""s skin. The coupling system attaches the proximal end of the fiber optic cable to the illumination device so that the proximal end surface of the fiber optic bundle is situated a fixed distance from the light source to receive light from the light source. Conventional coupling systems also permit the fiber optic cable to rotate relative to the illumination device while maintaining the proximal end in an engaged relation with the illumination device a fixed distance from the light source. Two techniques are known for such coupling systems.
In a first technique, a channel is provided on the exterior surface of the illumination device to receive the proximal end of the fiber optic cable. A 360xc2x0 slot is provided in the wall of the channel and a key slot is provided in the 12:00 position of the channel to provide access to the 360xc2x0 slot. The key slot and the 360xc2x0 slot are arranged such that during insertion of the proximal end of the fiber optic cable, a fixed protrusion provided on the proximal end of the fiber optic cable passes through the key slot into the 360xc2x0 slot. During insertion, the protrusion must be located at the 12:00 position so that the protrusion passes through the key slot. Because there is nothing blocking the key slot, very little force is needed to insert the cable into the illumination device. The proximal end of the cable is then rotated in the 360xc2x0 slot to move the protrusion on the cable away from the key slot. Engagement of the fixed protrusion on the proximal end of the fiber optic cable with the wall of the 360xc2x0 slot maintains the proximal end of the cable in engagement with the illumination device.
There is a disadvantage with the above-described technique for securing the proximal end of the fiber optic cable to the illumination device. If the proximal end of the fiber optic cable again rotates to the 12:00 position so that the protrusion is aligned with the key slot, the proximal end of the cable can freely disengage from the illumination device with very little force. At all other positions, however, the fiber optic cable cannot be removed from the illumination device without damaging either the cable or the illumination device, because the fixed protrusion on the cable contacts the wall of the 360xc2x0 slot.
In a second technique for securing the proximal end of the fiber optic cable to the illumination device, a 360xc2x0 slot is provided in the proximal end of fiber optic cable. There is no key slot to provide access to the 360xc2x0 slot. Instead, a protrusion is disposed on the wall of the otherwise smooth channel in the illumination device. This protrusion is retractable so that during insertion of the fiber optic cable into the illumination device, a force is required to cause the protrusion to retract. Once the proximal end of the fiber optic cable is sufficiently inserted into the channel in the illumination device, the protrusion on the illumination device is biased into an extended position by a spring so that it engages the 360xc2x0 slot in the fiber optic cable to maintain the cable in engagement with the illumination device.
There is a disadvantage with this retractable protrusion technique for securing the proximal end of the fiber optic cable to the illumination device. The fiber optic cable can disengage from the illumination device if the pull-out force on the cable is large enough to cause the protrusion to retract, regardless of the rotational position of the cable relative to the illumination device. Thus, even though some pull out force is required to cause detachment of the cable from the illumination device, detachment can occur, regardless of the rotational angle of the cable relative to the illumination device, if such a pull out force is applied to the cable.
Accordingly, it is an object of the present invention to provide a phototherapy system that overcomes the shortcomings of conventional phototherapy devices to extend the lifetime of such devices. This object is achieved according to one embodiment of the present invention by providing a phototherapy system that includes a base, a carriage assembly moveably coupled to the base, and a light transmission medium that selectively couples to the base. A first light source and a second light source are coupled to the carriage assembly. The carriage assembly is moveable relative to the base such that in a first position, the first light source is coaxially aligned with a proximal end surface of the light transmission medium to illuminate this surface. When the carriage is in a second position, the second light source is coaxially aligned with the proximal end surface of the light transmission medium illuminate this surface. A sensing device determines when there is a failure of the first light source, and the carriage assembly is automatically moved from the first position to the second position once a failure of the first light source is detected, assuming that the carriage was in the first position. If the carriage was in the second position and the sensing means detects a failure of the second light source, the carriage assembly is moved to the first position.
It is a further object of the present invention to provide a coupling system for selectively securing an end portion of a light transmission medium to an illumination device that overcomes the shortcomings of the coupling systems used in conventional phototherapy devices. This object is achieved according to one embodiment of the present invention by providing a coupling system that includes a collar provided on an illumination device. The collar includes a channel therethrough that receives the proximal end portion of the light transmission medium. A rotation slot is defined in a wall of the channel, and a key slot is also defined in the wall of the channel to provide access to the rotation slot. A fixed key pin is provided on an exterior surface of the end portion of the light transmission medium. The key pin is configured to pass through the key slot and fit within the rotation slot when the proximal end portion of the light transmission medium is inserted into said channel. The key pin is also moveable within the rotation slot once the proximal end portion of the light transmission medium is inserted into the channel to permit swiveling of the proximal end portion of the light transmission medium relative to the collar. A detent pin is provided in the key slot to prevent the key pin from freely disengaging from the rotation slot. The detent pin is moveable between a first position that permits access of the key pin to the rotation slot and a second position that blocks access of the key pin to the rotation slot. Such a coupling system prevents pull out of the light transmission medium from the illumination device in nearly all rotational angles, and over only a relatively small range of angles will some amount of pull out force cause the light transmission medium to decouple from the illumination device.
It is still another object of the present invention to provide a phototherapy system that combines the advantages of the automatic lamp replacement system discussed above and the advantages of the coupling system for selectively securing an end of a light transmission medium to an illumination device in a single phototherapy system.
It is yet another object of the present invention to provide a method of treating a patient using phototherapy that does not suffer from the disadvantages associated with conventional phototherapy techniques. This object is achieved by providing a method that includes first providing a phototherapy system having a base, a carriage assembly moveably coupled to the base, a motor assembly coupled to the carriage assembly for moving the carriage assembly between a first position and a second position, a light transmission medium selectively coupled to the base in a fixed position, a first light source and a second light source coupled to the carriage assembly, and a power supply coupled to the first and second light sources. The method also includes the steps of (1) placing an operative one of the first and second light sources in an operating position in which the light source is substantially coaxially aligned with the proximal end surface of the light transmission medium, (2) energizing the light source placed in this operating position by coupling the light source to the power supply, (3) monitoring whether this light source remains operative, (3) if not, moving the other light source to the operating position, and (4) energizing this other operative light source once it is moved to the operating position.